Electrical compensator



p 1940. L. BATCHELDER 4, 35

ELECTRICAL (-OMPENSATOR driginal Filed Jan. 6, 1933 2 Sheets-Sheet 1INVENTOR. LA UIZENCE BATCHEL 052 WWW.

Sept. 17, 1940. BATCHELbER 2,214,735

[ELECTRICAL COMPENSATOR Original Filed Jan. SL193: 2 Sheets-Sheet 2INVVEN TOR. LAURENCE 5A TCHELDEP Patented Sept. 17, 194

ELECTRICAL comnnsa'ron Laurence Batchelder, Cambridge, Mass, assign- -orto Submarine Signal Company, Boston, Mass,

a corporation of Maine Original application January 6, 1933, Serial No.650,535. Divided and this application Novem- 4 her 21, 1936, Serial No.112,058

4 Claims. (G14 17'Z386) This application is a. division of my copendingapplication Serial No. 650,535, filed January 6, 1933, issued August 3,1937, Patent No. 2,088,580, and relates to electric compensators.

the size that otherwise could be used. The sections could therefore bemade twice the size necessary to produce the maximum change ofretardation in the motion of the compensator switch allowable topreserve the continuity of the Electric compensators have been known fora impression to the observer. The result was that 5 considerable timeand have been used among a compensator of fewer sections could be builtother purposes for the directive reception of and that both theintermediary and final lines underwater noises and signals. Considerable.decould be made to have the same time lag. velopment along these lineswas first made dur- In my Patent No. 2,088,580, referred to above, ingthe World War when the use of the so-called I disclosed a furtherimprovement in the com- 1 multispot compensation was first evolved.Elecpensator switch whereby the number of inductive tric compensatorswere used with. a group of section elements could be reduced byutilizing a receivers submerged in the water, either mounted pair ofbridging coils which the compensator within the vessel or carried overthe side, for switch connects in parallel with the normal coils mdetecting the presence of other vessels such as of the retardation line.By this means it is posenemy submarines or warships. Compensators sibleto obtain a mid-series termination of the used in this manner have alsofound application line as well as the usual mid-shunt termination alongcommercial lines and have been used sucwhen only a. single two-terminalinductance is cessfully in preventing collisions between vessels used ineach section. This applied particularly m as well as determining thedirection of some to the binaural lines and made it possible to 20 knownsource of sound. reduce the number of coils in these lines to half In acompensator of the present type which the number previously used. may becalled a group compensator, the groups The present invention provides afurther imare first individually compensated and then comprovement inthe compensator switch and relates pensated as a whole between the twoindicating particularly to the maximum lines. In this case 25 ortelephone devices in the same general way as the number of coils andcondensers is not in the prior art. In the compensators of the reduced,but a perfect termination of each secprior art having a so-calledbinaural line, that is tion as the length of the line is varied is madethe line which compensates each group for a final possible whereby theaccuracy of the compen- 80 balance, a switching arrangement is usedwhich sator is increased. In the prior art the use of opens the linesuccessively at difierent sections. a pair of bridging coils which canbe connected The electrical contacts at the points where in parallelwith one of the coils of the retardathese openings occur are often poor,because of tion line has already been suggested but such dust or smallparticles which come between the arrangementshave not been for the samepur- 85 contacting surfaces with the result that some pose as in thepresent invention, namely to pro- 85 resistance is set up in thecircuit. This increases vide a proper termination of 'a portion of thethe resistance on the coil side of the line'and line when its length isbeing varied. Accordingproduces a distortional efiect which reacts veryto the present invention the bridging coils are unfavorably in creatingfalse observations and given the same inductance values as those of 40inaccurate balances when making a compensator the coils in the lineproper. 4o

setting. Besides this, the added resistance in- This andother featuresof the present invencreases the attenuation of the line. tion will beevident from the following descrip- In my copending application SerialNo. 600,191, tion taken in connection with the accompanying filed March21, 1932 issued February 16, 1937, drawings in which Figure 1 shows aschematic as Patent No. 2,070,570, I showed how these difliwiringdiagram of the compensator including the 45 culties could be overcome byemploying a switch retardation lines both binaural and maximumarrangement in which the line is varied at the and the compensatorswitch; Figure 2 shows a common side and the line is therefore preserveddevelopment of a part of the switch controlling intact while the switchis being moved from secthe maximum line; and Figure 3 shows schetion tosection. matically a modification of Figure l which never- 50 r Thisswitching arrangement had the further theless retains the advantages ofthe present inedvantage that it was possible to increase or devention. Icrease the length of the line a half section at In the present case theinvention is illustrated a time so that the sections could be made twiceas applied to a so-called six-spot system, but any number of spots maybe used and, in fact, other 55 in a plane or in a three-dimensionalspace.

arrangements than those indicated in the drawings may be employed, as,for instance, a circular group or a group forming other configurationsthe embodiment herein described six hydrophones are installed on thestarboard side of the vessel and six hydrophones on the port side.Selector switches are then provided so that the six starboardhydrophones may be employed to listen to sounds approaching from thestarboard side of the vessel or the six port hydrophones may be employedto listen to sounds approaching from the port side of the vessel, orthree of the starboard hydrophones and three of the port hydrophones maybe employed as a cross base to listen to sounds coming from ahead.

In Fig. -1 the coils of the port receivers are represented by I'p, 2'106'p while the coils of the six starboard receivers are indicated as Is,2's 6's. The hydrophones used in con-- nection with this compensator arematched directly with the lines on which the sound energy is impressed.The direct current flux excitation is supplied in series groups ofthree; the switches I3 and 9 applying the potential of thebattery I3across the common I4 and each of the groups of windings I2. A selectorswitch I5 is provided which has three positions: a bow position asindicated in the position shown in Fig. l, a port position when rotatedto the left and a starboard position when rotated to the right. For thebow position it will be noted that there is a choice of the use of theforward groups or the aft groups of three receivers. This choice may beeffected by the jumper connectors I and 8 which connect the switch arms9 and In to the connecting points F on the left or A on the right.

The jumpers I and 8 are preferably fixed when the installation is madefor the best choice on the vessel and thereafter are not changed unlessit is especially desired to do so. In the position of the jumpersindicated in Fig. 1, it will be noted that the forwardgroup F connectingwith I'p, 2'1], 3'3) and I's, 2's and 3's is used. In the position ofthe jumpers on the right contact points A the receivers lp, 5'10 and6'1) and 4's, 5's and 6's would be connected to the compensator. Theswitch 9 in its downward position is connected with the two switchpoints whose combination is designated 93. In this relation the jumpers6 sloping to the left energize the coils in the receivers Ip, 2'1), 3'10and Is, 2's and 3's. With the jumpers 8 in the other position the rearorthe end of the fixed or F-line while the receiver 3'12 is connectedatthe right end of the .C-line. The energies from the receivers thuscompensated in a fixed fashion are impressed by means of the connectinglead I6 to the common of onehalf of the B-line as indicated by thenumeral I1 applied to the right half of the ring I8.

Similarly the starboard half group is connected to the left'connector I9of the ring I8 by means of the connecting lead 2Il- In this case thestarboard receiver Is connected through the 43 position of the switch lconnects to the left end of the C-line while the receiver 3's connectsthrough the switch point 63 to the right of the C-line, and the receiver2's connects through the switch point 53 to the F-line. The energy fromthe three receivers is conducted over the line 22 to the B-line throughthe lead 2| and also to one terminal 23 of the binaural headphone 24.The other phone lead 25 connects to the opposite end of the B-line andsimilarly also one terminal of the phone 26 is connected to the otherextreme end of the B-line.

The description above illustrates the switching arrangement for theso-called bow position.

In the port and starboard positions the switch arm I is moved to theleft and right, respectively, that is to the left for the port positionand to the right for the starboard position. In the port position thereceivers Ip, 2'p and'3'p are connected to the left end of the C-line,the end of the F-line and the right end of the C-line,

contacts 62, and 63 and 64, 30 and 65, re-

spectively, unite the impulses passing through each F-line and itscorresponding C-line at the correct points to produce the desiredcompensation to compensate for the difference in time of arrival of thewave energy at the receivers of each group.

As will be noted, the switch contacts 62, 20 and 63 and 64, 30 and 65are adapted to move over the contact studs to 36, inclusive, and 31 to42, inclusive, respectively; each stud connecting to a different pointon the left and right C-lines, respectively. The contact switches 62, 20and 63, and 64, 30, and 65 move simultaneously on the same mechanism asthe ring I8 and the switch brushes 43, 51 and 44: the position of thecontact switches 62, 20 and 63, and 64, 30 and I 65 adjusting thecompensation of the C-lines and the position of the ring .I8 and thecontact brushes 43, 51 and 44 adjusting the compensation of the B-line.

As indicated in Fig. 1 the energy from the left F- and C-lines is fedinto the B-line by the two conductors comprising the lead I6 togetherwith a portion H of the ring I8 and the brushes 44 and 51 while theenergy from the right F- and C-lines is-fed into the B-line by means 'ofthe conductors 22 and 2| together with the portion I9 of the ring I8 andthe brushes .43 and 51. The ring I8 and the brushes 43, 51 and 44 movesimultaneously breaking the B-line each half section in its motion. Thisis accomplished as follows: 1

The B-line is composed of series inductances I 46, 46, etc., which withthe condensers 50, 50, etc., form the sections of the line. Thecondensers 50 are connected between the series inductances and thecommon. The line sections may be considered as either T sections or 1rsections, and are, in fact, first one and then the other, depending uponthe switch positions. It should be noted, however, that whether thesections are considered to be 1r or T sections, there is required onlyone twoterminal inductance coil-per section. The condensers 50,v 50,etc., are connected by means of the brushes 5i, 5I, etc., to the ringI8, while the inductances 46, 46, etc., are connected together in seriesand are also connected -at their junctions to the studs 52, 52, etc.

Between the halves l1 and I9 of the ring I8 there is an insulatingelement 53 which carries two conducting. segments 54, 55 spaced somewhatto position a but less than the width of the brushes 5| from thesegments i9 and I1, respectively, of the ring l8. These segments 54 and55 are connected to the segments I9 and il through condensers 56 and 56of the same capacity as the condensers 50.

Between the brushes 43 and 51 there is connected an inductance ll of thesame value as the effective series inductance per section of line.Likewise between the brushes 51 and 44 there is connected an inductance12 of the same value as the inductance II. By making the values of theinductances H and 12 of the same value as the efiective seriesinductance of the line, in this case substantially that of coils 46, theeffective terminating inductance for each half of the line will be equalto half of the inductance of coil 46 since both H and 12 are connectedin parallel with one of the coils 46.

In the C-lines the inductances are all connected in series and each oftheir connecting points are also connected to a contact stud. Thecondensers making up the C-lines are shunted between the connectingpoints of the inductances and a common. The adjustment of the C-lines isnot made by opening the common as in the case of the B-line, but byconnecting to the junction points of the series inductances. Y

The brushes 62, 20, 63, and 64, 30, divide each of the two C-lines intotwo parts, respective- .ly; Inductances 58, 59, 60 and BI are connectedbetween the several brushes, as shown, in order that the parts of theC-lines may be given proper terminations. The operation of the C-line adjustment is indicated in Fig. 2 by the development of the switchcontrolling the left C-line.

, In the position a the brushes 52, 63 are making connection with thecontact studs 35 and 35, respectively. The inductances 58 and 59 eachhave an inductance of a value one-half that of the eifective seriesinductance per section of line. The energy is taken oif the line throughthe brush 29 which in position a connects to the line only through theinductances 58 and 59. If we suppose the energies entering at each endof the line arrive in phase at coil 13, then coil i3 will be at acurrent node. Therefore, the coil 13 has no efiect at all and one halfof the line is terminated in the inductance 58 while the other half ofthe line is terminated in the inductance 59. Thus, since each coil 58and 59 has an inductance of a value one half that of the coil 73,

each half of the line will be terminated perfectly in a mid-seriesmanner by the coils 58 and 59.

In the prior art when a single brush was used, it was ordinarily made ofsufiicient width to connect at times simultaneously to two adjacentstuds. When the direction of sound was such as to produce a current nodein one coil, the proper setting of the switch would shortcircuit thiscoil and the line would not be properly terminated.

It will be apparent, however, that with the arrangement of the presentinvention, the C-line may be given perfect mid-series terminations.

Position b shows a transient position of the switch in which the lineterminations are being changed from those in position a to those inposition 0. In position 0 the brush 25 contacts with the stud 34 whilethe brushes 62 and 83 are not connected to the line. The inductances 58and 59 are therefore inoperative when the switch is in this position andboth theleft and the right parts of the line'have amid-shunttermination. The position d again shows a transient position of thebrushes while position e is similar one section advanced to the right.

In practice it is often convenient to use brushes and contact studswhich have a considerable width; If this is the case it is necessary tohave a certain relationship between the width and the spacing of thebrushes with respect to the width and spacing of the contact studs. Theproper width and spacing of the brushes with respect to the width andspacing of the contact studs will be apparent from a consideration ofFig. 2. Each of the three brushes 62,10 and 63 has the same width bwhile the distance between them isthe same as the width S of each of thestuds 3| to 36'. Then if we let P be the distance be-. tween centers ofadjacent studs and B be the total distance spanned by the three brushes,the following relations will hold:

b=0.5 P-S and 3:15 P-S It will be noted that the dimensions of thedevelopment of the switch as shown in Fig. 2 agree with the aboveformulas. The specific example shown, however, is a particularlyconvenient one inasmuch as the width of the brushes b is made equal tothe width S of the studs. It will be observed, however, that-any desiredchoice can be made of either b or S and that such choice will determinethe value of the other dimensions.

Fig. 3 shows schematically an alternative manner of connecting. thehydrophones and telephones to the retardation'lines from that shown inFig. 1. In theembodiment described in Fig. 1 the C-lines are shown asfeeding to the center of the B-line through the brushes 53, 51' and 46while the telephones are connected to the ends of the Bline. It will beobvious, however, that the opposite system may be employed if desired.This is shown in Fig. 3. In this figure the C-lines feed to the ends ofthe B-line and the telephones are connected to the center of the B-linethrough the brushes 43, 57 and M.- An important difference between thetwo is that with the latter arrangement the two C-lines musthave'separate com-- On the other hand, if separate commons binauralmethod or by the minimum perceptible difference in the maximum method ofobservation, and the spacing of the hydrophones. Usually the size of asection is approximately 1.8 waterinches. In the present case I may usea section having about 3 water inches retardation and may also use thesame size section for the C-line. In the present invention the 13-, C-and F-lines have the same cutofi frequency and have their. impedancesrather well matched and absolutely matched under the same conditions oftermination of the B- and C -lines.

When the compensator is used for the maxi-- mum method the switch I0must be closed. This switch connects the secondaries of the transformer68 and 69 in parallel for the maximum method. The primaries of thetransformers 68 and 68 are matched to the line. The transformers maybeomitted if it is desired only to use the binaural method or if, as abovedescribed, the C-lines have separate commons.

While the invention has been described above as applied to a'compensator for use in systems for finding the direction of a source .ofsound waves, it will be apparent that it has other applications.Furthermore, it is useful not only in connection with retardation lineshaving series inductances and shunt capacitances, but also with othertypes of artificial lines or series -of electrical structures. It shouldbe noted that the line may be composed of impedances in any formincluding,

mutual inductance if desired and that the bridging elements may beimpedances of any suitable form. The bridging elements and a switch ofany of the types described may, for example, be used with a lattice lineor with a line having series capacitances and shunt inductances.

Accordingly, it will be appreciated that the present invention can beembodied in other forms and therefore I do not desire to limit myself tothe embodiment herein described, but I claim:

1. An electric compensator including an artificial line comprisinginductive series elements each having an inductance of L and capacitiveshunt elements forming sections of the line, switching means foradjusting the length of the line and adapted to place two seriesconnected inductance elements each having an inductance of taining aseries impedance element having only two terminals with means forefiectively connecting to the electrical center .of one of saidimpedance elements including a pair of series connected impedances eachhaving one half the impedance of said series impedance elements andbeing adapted together to be connected inparallel with one of saidseries impedance elements and means for transferring electric energy tothe common terminal of said series connected lmpedances.

' 3. In an electric compensator including series and shunt impedanceelements forming s ti of an artificial line, switching means for varyingstuds, the widths and spacing of the brushes being so adjusted withrespect to the width of the studs that the width of each brush is 0.5P--S and the total span of the three brushes is 1.5 P-S where P is thedistance between centers of adjacent studs and S is the width of eachstud.

4. The combination of an electric retardation line having a series ofrecurrent sections each containing a series inductive impedance element,means for feeding electrical energy to the line between an interiorsection and each end of the line, said section being in such a positionthat there is a current node in its series impedance element, said meansincluding a switching device having a center tapped impedance elementadapted to be connected in parallel with one of said line impedanceelements and said center tapped impedance element having an inductanceequal to the inductance of said line impedance element.

LAURENCE BATCHELDER.

